caa a22 4500 397570198 CHVBK 20180308164839.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1093/oxfordjournals.jmicro.a023421 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jmicro.a023421 Tungsten-Point-Cathode Electron Gun Using Electron Bombardment for Cathode Tip Heating: Cathode Life and Operating Characteristics at Cathode Temperatures above 2,800 K [Elektronische Daten] [Ryo Iiyoshi, Susumu Maruse] A new type of tungsten point cathode electron gun was operated at higher cathode temperatures (≥ 2,800 K), and its cathode life and operating characteristics were examined. In this gun, a straightened tungsten wire is used as the cathode, and the tip is locally heated by a disk-shaped electron beam from a heater assembly set inside the Wehnelt cylinder. The electron beam heating confines the cathode evaporation to the tip part and improves the working life of the cathode at higher temperatures, or emission current densities. At 3,150 K, the gun provides a stable beam with the Langmuir's theoretical brightness, where the brightness is one order of magnitude higher than the conventional hairpin cathode gun. The cathode shapes after the gun operation, the measured evaporation rate of the cathode tip, and the estimated relation between the cathode life and the beam brightness are described. © 1996 Oxford University Press Full-length Papers nationallicence electron beam nationallicence electron gun nationallicence tungsten point cathode nationallicence cathode life nationallicence electron beam heating nationallicence Iiyoshi Ryo Department of Electronics, Aichi Institute of Technology, Yagusa, Toyota, 470-03 Japan, Tenpaku-ku, Nagoya, 468 Japan aut Maruse Susumu Meijo University Tenpaku-ku, Nagoya, 468 Japan aut Microscopy Oxford University Press 45/2(1996-04), 128-134 0022-0744 45:2<128 1996 45 jmicro https://doi.org/10.1093/oxfordjournals.jmicro.a023421 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jmicro.a023421 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Iiyoshi Ryo Department of Electronics, Aichi Institute of Technology, Yagusa, Toyota, 470-03 Japan, Tenpaku-ku, Nagoya, 468 Japan aut NATIONALLICENCE 700 1- Maruse Susumu Meijo University Tenpaku-ku, Nagoya, 468 Japan aut NATIONALLICENCE 773 0- Microscopy Oxford University Press 45/2(1996-04), 128-134 0022-0744 45:2<128 1996 45 jmicro Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford